软土场地三塔斜拉桥纵向减震体系研究  

Study on Longitudinal Seismic Mitigation Systems for Three-Tower Cable-Stayed Bridges on Soft Soil Sites

作　　者：蒋湘平 张鹏辉 王志平 刘振标[1,2] 李建中 JIANG Xiangping;ZHANG Penghui;WANG Zhiping;LIU Zhenbiao;LI Jianzhong(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;China Railway Construction Bridge Design and Research Branch,Wuhan 430063,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063 [2]中铁建大桥设计研究院,武汉430063 [3]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《铁道标准设计》2024年第9期95-103,共9页Railway Standard Design

基　　金：国家自然科学基金重点项目(51838010);中铁第四勘察设计院集团有限公司科技研究开发计划项目(2021K011,2020K004)。

摘　　要：为控制软土场地三塔斜拉桥在强震中的纵向位移,同时使上部结构惯性力在3个桥塔中均匀分配,以跨径435 m的双主跨三塔组合梁斜拉桥为背景,建立中塔设固定支座-边塔设阻尼器、三塔均设阻尼器、中塔弹性连接-边塔设阻尼器3种减震体系的有限元模型,采用非线性时程分析方法对每个体系进行阻尼器参数敏感性分析并拟定合理的参数。基于得到的最优阻尼器参数,对比3种减震体系的动力特性、位移/内力响应及阻尼器减震率,并分析各体系的中边塔内力差。研究表明:中塔弹性连接-边塔设阻尼器体系的弹性约束刚度宜为1.0×10^(4) kN/m;拟定3个体系的合理阻尼参数分别为α=0.1/C=8000,α=0.3/C=5000,α=0.3/C=7000;中塔设固定支座-边塔设阻尼器体系周期小、地震力大且边中塔的剪力与弯矩差率高达-57.9%、-45.1%,在设计中不宜选用此体系;其余两个体系具有较好的抗震性能,梁端位移减震率分别为47.44%与41.78%,边中塔弯矩差率均仅为18.6%,综合来看,三塔均设阻尼器体系的减震效果及三塔分配地震力的均衡性略优;进行同类桥梁抗震设计时,建议选用三塔均设阻尼器体系或中塔弹性连接-边塔设阻尼器体系。To control the longitudinal displacement of three-tower cable-stayed bridges on soft soil sites during strong earthquakes and ensure that the inertial forces of the superstructure are evenly distributed among three bridge towers,a finite element model was established for three seismic mitigation systems based on a double-main-span three-tower combined beam cable-stayed bridge with a span of 435 meters.The three systems were:(1)a middle tower with fixed bearings and edge towers with dampers,(2)all three towers with dampers,and(3)a middle tower with elastic connections and edge towers with dampers.Nonlinear time-history analysis was performed to conduct sensitivity analysis on damper parameters for each system,and reasonable parameters were determined.Based on the optimal damper parameters obtained,the dynamic characteristics,displacement/internal force responses,and damper reduction rates of the three systems were compared.The internal force differences between the middle and edge towers were analyzed.The results indicated that the optimal restraint stiffness for the elastic connection-damper system should be 1.0×10^(4) kN/m.The proposed damper parameters optimal for the three systems wereα=0.1/C=8000,α=0.3/C=5000,andα=0.3/C=7000,respectively.The fixed bearing-damper system exhibited a short period and high seismic forces,with a shear force and bending moment differential rates between the middle and edge towers of up to-57.9%and-45.1%,making it unsuitable for seismic design.In contrast,the other two systems demonstrated better seismic performance,with displacement mitigation rates of 47.44%and 41.78%at the beam ends,and a bending moment differential rate of only 18.6%between the middle and edge towers.Overall,the system with dampers on all three towers provides slightly better seismic mitigation and more evenly-distributed seismic forces.Therefore,it is recommended to use either the system with all three towers equipped with dampers or the system with an elastically connected mid-tower and damper-equipped edg

关 键 词：铁路桥 斜拉桥 软土场地 抗震性能 减震体系 阻尼器 

分 类 号：U24[交通运输工程—道路与铁道工程] U442.5[建筑科学—桥梁与隧道工程] U448